Reluctant to admit mistake getting wine (6)
I believe the answer is:
sherry
'wine' is the definition.
(sherry is a kind of wine)
'reluctant to admit mistake' is the wordplay.
'reluctant' becomes 'shy' (I've seen this in other clues).
'to admit' means one lot of letters goes inside another.
'mistake' becomes 'err' (to err is to make a mistake or blunder).
'shy' going around 'err' is 'SHERRY'.
'getting' is the link.
(Other definitions for sherry that I've seen before include "Christmas drink?" , "Fortified 1 down [WINE]" , "Pre-dinner aperitif as from Jerez" , "Strong sweet wine as aperitif" , "Wine from Spain's Jerez region, drunk as an aperitif" .)